This invention generally relates to a fuel injector for a combustion engine. More particularly, this invention relates to a fuel injector that heats fuel to aid the combustion process.
Combustion engine suppliers continually strive to improve emission and combustion performance. One method of improving both emission and combustion performance includes heating or vaporizing fuel before injection into the combustion chamber. Heating the fuel replicates operation of a hot engine, and therefore improves combustion performance. Further, alternate fuels such as ethanol perform poorly in cold conditions, and therefore also benefit from pre-heating of fuel.
Various methods of heating fuel at a fuel injector have been attempted. Such methods include the use of a ceramic heater, or a resistively heated capillary tube within which the fuel passes. These methods require electric power and therefore leads that extend through pressure barriers and walls. Seals required between the wires and pressure barriers are a potential source of fuel leakage and are therefore undesirable. Further, such heat generating devices must be insulated from other fuel injector components and therefore are difficult to implement and support within a fuel injector.
One consideration for all automotive components is the number of connections to any electronic or electromechanical device. The more terminals and wired connections the more support connections to electronic control units and other control devices. Each additional terminal adds cost in materials and assembly time.
Accordingly, it is desirable to design and develop a method of heating fuel without creating additional fuel leak paths, or insulating structures while minimizing the number of electrical connections and still providing for the heating and vaporization of fuel.